August 19, 2012

Repairing a Quarter Wave HT Antenna

About ten days ago I was getting ready for a public service event and almost poked myself in the eye with the end of the thin quarter-wave whip antenna that was attached to my Yaesu VX-7R handheld radio.

The radio had been in the backseat of my truck inside the nice Blackhawk radio harness I use. Unbeknownst to me, the tiny plastic tip at the end of the antenna had come off the antenna since my last public service event.

Over the years I've come to depend on clear, fast-setting epoxy for many a repair job. There was no doubt that my two bottles of Loctite epoxy would solve my problem in minutes.

I mixed one droplet each of the resin and hardener with a toothpick on a small block of wood. Prior to doing this I had set up an adjustable wrench with the jaws adjusted so they would allow the antenna to suspend upside down allowing the droplet of epoxy to form on the tip of the antenna. I even put down an old magazine on the floor to catch any excess drippings.

The epoxy I use sets up in five minutes or less. My initial thought was that a droplet would form on the tip of the antenna on its own and all would be well. I dipped the bare metal into the freshly mixed epoxy, twirled it once to evenly spread it on the wire, set it carefully into the open jaws of the wrench and walked away.

When I came back five minutes later I was shocked to see there was just a thin coating of the epoxy on the wire. The tear shaped droplet I had created was gone. Most of the epoxy had fallen onto the magazine.

It was time to start over. I did everything the same way, but I held the antenna in my hands sideways and twirled it for two or three minutes making sure the droplet of epoxy did not fall off. I was doing pretty much what you see glass blowers do with a glob of molten glass on the end of their blowing rods.

Before I knew it the epoxy had set up enough that it was not going to drip off. I then set the antenna into the jaws of the wrench to harden up for about an hour.

Victory! The epoxy worked great, and is really holding on. In my go bag I'll put a small roll of electrical tape in case it happens again out in the field. I'm sure other plastic dip compounds or other materials will produce similar results, but for me Loctite clear epoxy is #1 on my depth chart of repair materials.